adult dog poops in house when its raining out

Question
What the heck do I do my adult dog (I got a few months ago) has started pooping in the house when it is raining or even wet outside.  Of course she has to go on my 1 floor that has carpeting.  She is a 2 year old spayed female smooth coat  collie.    She is good natured and usually content to lay around and chew bones or play fetch with us.  She does love to go on walks and I don't take her when I have to work  super late (I work nights/husband works days)which is maybe 1-2 days a week.  I  do crate her when we are not home but it is usually only from 5 am to 7 am - the little window someone is not home with her. Also, I  have been gradually increasing the time she is left alone in the house- while I am out in the garden.  So far she is up to an hour and a half with no issues.  What am I doing wrong?

Answer
You seem to have a couple of issues.  You need to pay more attention to her learning the times she needs a bowel movement and her behavior at that time.  Close off the carpeted room to her, close the door, set up a gate, whatever, to keep her out of it when you can't watch her.  When she needs to go out when it is raining, dig out your rain coat or umbrella and take her out.  Walk her around until she does have her bowel movement.  They can only walk and hold it so long.  Then lavish praise on her and let her go back in.  It may take a while, but she should eventually accept that she must go out, and if it is raining, the quicker she goes about it, the quicker she gets back in.  

Although I have a fenced area in the back, I sometimes tether the dog out there when I am working out front.  There is nothing wrong with that as long as you are around and the dog is content.  Some of my puppies have fussed, and I have had to take them back inside to the crate.  You might try that to reduce the time the dog spends in the house by itself.